This invention is for the primary purpose of providing potassium permanganate solutions with a greater ability to release oxygen.
This method is especially useful in causing greater amounts of oxygen to be released from a potassium permangamate solution than when the permanganate is used in a water solution in the conventional method of air scrubbing to remove pollution.
Heretofore, much of the oxidation potential of potassium permanganate in air scrubbing systems has been wasted by the loss of oxygen in a sludge to be disposed of. It is my discovery that much more of the oxygen in the potassium permangante can be liberated and taken up by the air if auxiliary chemicals are used with the potassium permanaganate as stated in the abstract hereof.
It is my belief that heretofore the silicates were never tried in combination with potassium permanaganate perhaps because no one ever thought of trying them because silicates are usually insoluble compounds, thereby giving silicates in general a seemingness of not being workable.
Many commercial silicates were among those that I tried, but they did not work because their formulas were not sufficiently unbalanced and "hungry" for acquisiting of a metal constituent.
The silicate I have found to be successful as a co-reactant of the second group is a readily available commercial solution of approximately 40% solution of sodium silicate of formula Na.sub.3 Si.sub.3 O.sub.7 that is commonly called egg preserver.
To my knowledge, no one has ever tried sodium bisulfate in an air scrubber solution. Of course, it would not work without the permanganate compound.
I tested sodium bisulfite as a co-reactant of the second group, but it didn't prevent the waste of oxygen.
The history of air scrubbing with potassium permanganate began in the early part of this century, perhaps even in the last century, and engineers and chemists have always been trying to reduce the cost of air scrubbing. But, to my knowledge, through all of these many decades there has not been proposed an industrially acceptable way to scrub air any cheaper than with the oldest established method, potassium permanganate alone.
Permanganates have been used to oxidize polluted air for many years, usually in a wet scrubber system where the resultant absorbed polluted matter and waste manganate in the form of a solid insoluble residue as manganese dioxide accumulates. My invention is not concerned with what is oxidized or removed from the air, but has resulted in a need to improve the efficiency of the costly use of permanganate.
I have discovered that a common, easily obtainable article of commerce "silicate of soda", an alkaline solution containing mixtures of various sodium silicate compounds, can improve the oxidizing efficiency of the permanganates. A constituent having the formula Na.sub.2 Si.sub.3 O.sub.7 is believed by me to be the active ingredient of my invention since the ratio of metal to silicate radical is low. In other words, the compound is "imbalanced" or deficient in metals and would, therefore, have a tendency to take on another metal, if in proper form and under proper conditions.
A British Patent to James william Abson et al, U.S. Pat. No. 1,152,705, issued May 21, 1969, and titled: Improvements in or Relating to the Treatment of Materials Comprising Compostible Organic Matter, is of interest, but I take exception to the general use of acidity. There are many types of acids, both organic and inorganic. Citric acid, an organic acid from citrous fruits, doesn't work in my process, since its manganese salt is insoluble, and therefore, produces a nuisance sludge which my invention teaches how to avoid. He uses sulfuric acid, a liquid which is dangerous and difficult to handle.
I teach the use of an acidic sodium sulfate salt which is a solid, can be handled more easily and safely, and is not as strongly acidic. The minimum amount used should be in excess of twice the equivalent molecular weight of the permanganate.
As regards the patent to Eugene O. Brimm, U.S. Pat. No. 2,427,708, issued Sept. 23, 1947, and titled: Chemical Production of Oxygen, I find little similarity to my teachings. I have found that in an aqueous air scrubber system, sodium metasilicate does not prevent the formation of a sludge as a co-reactant with permanganate. As mentioned, I add permanganate to the scrubber system, not manganate.
To produce oxygen with the process of Brimm, a high heat in the form of steam is necessary, which would be very expensive for a simple oxidation-reduction, as occurs to remove offensive odors in my process.
The efficient use of oxygen by my process at a plant depends on the proper operation of equipment.
The prevention of nuisance sludge formation by the use of my process, as claimed, is easily observed with the eyes.
In my opinion it is likely that sodium bisulfate has never been thought of as a possibility for use with potassium permanganate in scrubbing. This has been so even though sodium bisulfite has been used to clean up potassium permanganate waste material, the waste material being manganese dioxide, which is inert and useless. Sodium bisulfite and sodium bisulfate are both acidic and I believe there is a tendency not to consider acid compounds because of their corrosive effect on equipment, causing acid-resistant equipment to be necessary, which probably would usually be thought to be excessively expensive. However, I have discovered that sodium bisulfate can be used with the potassium permanganate and when this is done, the results are so valuable that the cost of acid-resistant equipment is very affordable after all. In fact, I've discovered that the cost benefits of a sodium bisulfate teamwork with potassium permanganate are enormous.
Sodium bisulfate has been used in the prior art to get rid of the manganese dioxide sludge so that it is disposed of, but wasted. I propose to prevent this waste this waste of the manganese dioxide sludge because it contains valuable oxygen which is excellent for oxidizing odors and thereby assisting the potassium permanganage in its job of oxidizing odors. The result is that the process I propose is more efficient cost-wise since it uses less potassium permanganate for a given amount of air scrubbing.
A further object of this invention is to provide a process which requires less maintainance of the equipment, specifically less clean-out is needed. In the prior art the manganese dioxide would foul up the scrubber and packing and valuable time would be needed to clean out the manganese dioxide. Such clean-out time is what is called as "down time". In other words, during this clean-out in the prior art the air scrubber is non-functional.
In the prior art extra containers for cleaning solution were an expensive part of a scrubbing system when sodium bisulfite was used. This also required an extra pump and extra expense. It is an object of this invention to eliminate that unnecessary extra expense.
A particular object is to provide a new process for this purpose which produces as useful both fertilizer and water. The importance of not wasting water is often overlooked. However, in any city there are persons glad to pay for water from a city to carry it by tank truck to needed locations.
My process also produces valuable fertilizer in various modifications of the process. For example, the chemical resultant product of reaction in this process with sodium silicate being a second co-reactant produces valuable fertilizer. Valuable fertilizer is also present in the resultant product when the second co-reactant is any one of the phosphates listed or potassium silicate, or any of the sulphates listed, or potassium itself. It seems to me that it is very important that the resultant product has such a needed use as fertilizing farm crops.